A system on chip (SOC) is an integrated circuit that integrates several components of a computer system into a single semiconductor chip. The SOC may be a component of a larger computer system or network, and can be supported by a printed circuit board (PCB) connecting the SOC to other circuit components and communications channels. Often, in working with complex SOCs, it is necessary to provide the input/output interfaces (I/Os) with reference clocks that are used to establish a timing base for generation of internal clocks used to transmit and receive data. A single SOC may interface with several different communications protocols, each of which may require different reference clock frequencies. In typical SOCs, these reference clock signals are generated off-chip and provided to the IOs through buffered channels on the supporting PCB.